1. Field of the Invention
The present invention relates to a method of and an apparatus for controlling fermentation, and more particularly to a method of and an apparatus for controlling the fermentation of moromi mash.
2. Description of the Relevant Art
During fermentation of moromi mash in the process of manufacturing soy sauce or shoyu, soybean protein and wheat starch are progressively converted to amino acid and glucose, respectively, by koji-mold. A portion of the glucose is then progressively converted to alcohol and lactic acid by yeast and lactic acid bacteria, respectively. In the moromi mash fermentation, therefore, amino acid and glucose are produced from soybean protein and wheat starch, respectively, and alcohol and lactic acid are produced from the glucose. After the fermentation, ripened moromi mash is pressed to produce raw soy sauce. The quality of raw soy sauce is greatly affected by the balancing of the amounts produced of glucose, lactic acid, and alcohol. In order to adjust the concentrations of these ingredients to desired levels, the moromi mash or its liquid is extracted periodically during the fermentation process to analyze the ingredients. Based on analytic results, yeast and lactic acid bacteria are added to the moromi mash, and aeration and temperature of the entire moromi mash are adjusted.
Nitrogen, which is indicative of the concentration of amino acid, is analyzed by the Kheldahl method, and alcohol is analyzed by gas chromatography. Glucose and lactic acid are analyzed mainly by the enzymatic method. Glutamic acid, which is an amino acid and governs the flavor of soy sauce, is also analyzed mainly by the enzymatic method. These analytic processes have heretofore been effected manually over long periods of time using independent analyzing devices. The analysis of nitrogen, particularly, has required several hours. Therefore, a prolonged period of time is needed to carry out the analytic processes, add yeast and lactic acid bacteria based on analytic results, aerate the moromi mash, and adjust the temperature of the moromi mash. Since the ingredient analysis and the subsequent processing steps are effected at periodic intervals, it has been difficult to increase the efficiency of and automate the process of fermenting moromi mash. Therefore, an efficient and automated device for fermenting moromi mash has not been available in the art.
The present invention has been made in an effort to solve the above problems with the conventional method and apparatus for fermenting moromi mash.